A recent change is breaking the Echo-Notfication-List and the hovercard extension, probably other scripts too.
It is caused by blocked calls to https://bits.wikimedia.org/event.gif? (blocked e.g. by Firefox with Adblock Plus).
I suspect this is caused by https://gerrit.wikimedia.org/r/182890 (which was also backported to wmf13 and 14)
Reports:
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Resolved | • Prtksxna | T86900 FF 35: hovercard conflicts with ad block extensions: doesn't disappear, and new hovercard don't pop up | |||
| Duplicate | None | T86918 Recent EventLogging change breaking Echo, Popups on blocked event.gif calls / on Firefox with Adblock Plus |
Yesterday for me this also broke the rendering of CPB on top of https://www.mediawiki.org/wiki/Special:Notifications?debug=true for me (icons way lower than text); JS console showed a wonderful line with just one colon, pointing to https://bits.wikimedia.org/static-1.25wmf14/extensions/EventLogging/modules/ext.eventLogging.core.js :222 - today that looks okay again, don't know.
Popularity of Adblocker tools in browsers might trigger a variety of "interesting" issues brought up on Village Pumps etc, hence this should be pretty high priority.